正渗透技术在水和废水处理中的应用研究

正渗透(Forward osmosis,FO)技术是一种由渗透压驱动的膜技术,与传统的机械压力驱动的膜技术相比,具有出水水质高、能耗低、操作压力小、设备简单易操作、污染小等特点,近年来在水和废水处理的研究领域受到越来越多的关注.但FO技术目前仍然存在一些问题,如浓差极化、膜污染、汲取液溶质返混和汲取液的后处理等,使之目前仍未得到广泛的应用.本文对已有FO技术的相关文献进行较为全面系统的归纳,介绍了FO技术的原理,以及在海水脱盐、市政污水处理、特种废水处理等领域的应用,讨论了影响FO运行的主要因素(主要包括FO膜、汲取液、原水性质和运行条件等方面),并着重阐述了FO技术目前存在的问题(浓差极化、膜污染、汲取液溶质返混和汲取液的后处理).最后,对FO技术未来的研究和发展方向给出了建议.

Forward osmosis technology applied for water and wastewater treatment

Forward osmosis (FO) is a kind of membrane separation technology driven by osmosis pressure. Compared with the conventional membrane technologies driven by mechanical force, FO features good quality of produced water, low energy consumption, low operational pressure, easy equipment operation and low fouling, etc. FO has therefore attracted growing attention in water and wastewater treatment research fields. However, there are still some challenges why FO has not been wide applied yet, such as concentration polarization, membrane fouling, reverse solute diffusion and post-treatment of the draw solution, etc. In this paper, based on summarizing a large amount of the published works, we introduce the FO principle and the potential applications of FO, e.g. seawater desalination, municipal wastewater treatment, special wastewater treatment, etc. The main affecting factors on FO process (e.g. FO membrane, draw solution, feedwater, operational conditions, etc.) have been discussed. The existing problems of FO have also been addressed in term of concentration polarization, membrane fouling, reverse solute diffusion and post-treatment of draw solution, etc. Finally, the future research and development direction of FO has been proposed.